1. Field of the Invention
This invention relates to a method of imaging a visualizable corporeal situs by radiological imaging techniques, comprising delivery of the situs of an imagingly effective amount of an imagingly effective, physiologically acceptable reagent, as well as to contrast media reagents useful for such imaging.
2 Description of the Related Art
In fields such as angiography and gynecology, as well as in other medical diagnostic and treatment fields, radiological imaging reagents are employed. These reagents are typically delivered to the corporeal situs to be visualized, and then the associated corporeal region is subjected to radiation (e.g., X-ray) exposure and fluoroscopic analysis.
By way of example, radiological reagents (sometimes hereinafter referred to as "contrast media", "contrast media reagents", or "imaging reagents") are delivered to a coronary situs in coronary angioplasty by means of an angiographic syringe or injector, which directs the contrast media through a catheter or other passage means into the appropriate coronary lumen. Vascular plaques are similarly visualized by catheter-mediated introduction of contrast medium to the vascular lumen, in connection with potential use of arterial angioplasty techniques (e.g., balloon angioplasty or laser angioplasty), by means of which the vascular plaque is treated to deocclude the arterial lumen. In gynecological diagnosis, an imaging reagent may be transcervically introduced by a syringe, pump, or injector, following which the pelvic region is radiologically visualized.
Contrast media reagents comprise a constituent imparting radiopacity thereto, typically an iodine-based compound which is physiologically acceptable, e.g., organically-bound iodine, or iron chelate complexes of iodine. Examples of commercially available iodine-based radiological imaging reagents include the iodine-based radiopaque contrast medium formulation which is commercially available under the trademark VASCORAY.RTM. from Mallinckrodt Corporation (St. Louis, Mo.).
Among the deficiencies attending the use of conventional iodine-based radiological imaging formulations is the fact that the active ingredients imparting radiopacity to the contrast medium formulation typically are not degradable into physiologically acceptable by-products and residues. Accordingly, the contrast medium must be completely removed (flushed, or otherwise extracted) from the corporeal system following visualization of the desired situs.
Second, the active ingredient of such conventional imaging formulations frequently has a relatively low concentration or "loading" of iodine associated therewith, as a result of which relatively high dosages of the contrast medium are required.
Third, the active ingredients employed in radiological imaging formulations frequently are poorly soluble in the carrier medium of the formulation.
Accordingly, it would be a substantial advance in the art to provide a radiological imaging reagent which (i) is physiologically acceptable, (2) is highly effective, (3) comprises an active ingredient which is water soluble so that water may be employed as the solvent medium of the reagent formulation, (4) is degradable to physiological acceptable by-products and residues, which are readily metabolized and/or excreted in normal functioning of the corporeal system, and (5) is characterized by a high concentration or loading of iodine.
Relative to the radiological visualizing method, and contrast media reagent species of the present invention, relevant art is described below.
U.S. Pat. No. 4,847,065 to A. Y. Akimova et al discloses iodine-containing radiopaque organic acids, as described at column 3, lines 15-21 of the patent.
U.S. Pat. No. 4,713,235 to R. E. Krall discloses organic iodo agents, particularly iodo carboxylic acids, as radiopaque agents in acrylate-based occlusion compositions for female sterilization. The iodine reagents are discussed at column 3, line 20 to column 4, line 22 of the patent.
As mentioned above, a diagnostic radiopaque formulation is commercially available from Mallinckrodt, Inc. (St. Louis, Mo.) under the trademark VASCORAY.RTM.. This contrast media formulation is a phosphate-buffered solution containing organically bound iodine.
Commercially available diagnostic radiopaque media are variously used in aortography, angiocardiography, and excretory urography.